How do I add a Clothing model to an unclothed model?
I figured it out now

STEP 1
Unlink clothing from model
STEP 2 
If its bigger and above the model, set x y z scales to .2525
Step 3
Append the object and parent it to main mesh with "Armature Deform" option, none of the ones below. ( Thats because i already weight painted the windbreaker )